HUNTINGTON, W.Va. – Dr. Kumika Toma of the Marshall University College of Health Professions has received a research award to study sex and age differences in skeletal muscle responses to weakness and recovery. As part of a NASA-funded project in space biology and medicine, Toma’s study is aimed at better understanding how microgravity will impact crew members on extended missions.

Toma, program director for the undergraduate exercise science program in the college’s School of Kinesiology, said the study will use rats to examine the long-term exposure to microgravity.

“Seemingly, there are sex and age differences among the degree of muscle weakness and also the degree of recovery,” Toma said. “This study uses rats whose hind limbs will be suspended for a week so that they don’t use hind limbs. After one week of hind limb suspension, they will be back to their normal activity (recovery). Since the diameter of skeletal muscle is correlated to the muscle strength, I’ll be able to see the muscle size differences among sex and age. If there are differences, then, we can develop age- and sex-specific tactics to minimize loss and maximize recovery.”

Toma said decreased skeletal muscle size, or what is known as atrophy, due to space flight is well known and research has been conducted to investigate the degrees of atrophy and recovery.

“The principle of skeletal muscle is ‘use it or lose it,’ ” Toma said. “In the environment of microgravity, muscle hardly works because there is no resistance. The skeletal muscle of astronauts is weak and since NASA estimates about nine months of space flight, significant muscle atrophy occurs among Type I muscle fiber and other adverse health effects are a major concern. Given the range of expertise required for a Mars mission, it is anticipated that crew members may be diverse in age and sex. However, there is no systematic study investigating the age and sex differences of skeletal muscle atrophy and recovery.”

Dr. William Pewen, associate dean of research for the college, noted, “Future extended missions will require crews with greater breadth and depth of expertise and experience, so we must ensure their ability to perform successfully. At the same time, Dr. Toma’s work will add to our knowledge on the loss of function which so many experience when illness or disability restricts activity – a critical problem right here on the ground.”

Toma said because microgravity is the example of extreme disuse, the results from this study will be applicable to anyone who is sedentary or bedridden. She will finish collecting data by March 2015 and after months of data analysis, she will have the initial research report completed by September 2015. Toma said she plans to apply for another grant to extend her research project into the following year.

Photo: Dr. Kumika Toma has conducted her microgravity research with the microscope featured in this photo. This microscope was used by the late Dr. Gary Dudley, who started a muscle study for NASA 20 years ago at Marshall University in the basement of Gullickson Hall.

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